OBJECTIVES: 1. To determine the synaptic linkage of reticulo-oculomotor and abducens pathways utilizing intracellular recording. These experiments will be performed acutely in anesthetized animals. 2. To determine the cells of origin of reticulo-oculomotor and abducens projections, these cells will be identified by stimulation of their axons in the region of the IIIrd or VIth nuclei and recording antidromic responses from cell bodies in the reticular formation. Once these reticular cells are identified as projecting monosynaptically to the oculomotor and abducens nuclei, sites in the brain stem, thalamus and spinal cord will be stimulated and effects upon reticular neurons surveyed with the microelectrodes. VIIIth nerves will also be stimulated to evaluate vestibulo-reticular interaction.